Just seen this thread, i did lots of experimenting with 4g 5g huawei routers, in 2 locations, middle of a council housing estate with no clear line of sight to mast, other in country side with reasonable unobstructed route to mast. Smarty do unlimited sim for £20/month cancel renewal at any point and it runs to the end if your current 30 day period so very easy to cancel. Worst case performance, b525 ran at about 6meg down, b818/h112 gave about 20 meg down. At peak times might drop to a couple if megs intetmittenly. Best location, country side, 40+ meg constant, could get more too with ee.
Down side latency is about 60, on vm it is 2-3.
The h112 5g router was fastest but the phone socket wouldnt work so no way to make phone calls over the sim card. I sold the 5g router and kept the 4g 818.